Robin Hack discovered that the nss_files database did not
correctly implement enumeration interleaved with name-based or
ID-based lookups. This could cause the enumeration enter an
endless loop, leading to a denial of service.

Arjun Shankar discovered that the _r variants of host name
resolution functions (like gethostbyname_r), when performing DNS
name resolution, suffered from a buffer overflow if a misaligned
buffer was supplied by the applications, leading to a crash or,
potentially, arbitrary code execution. Most applications are not
affected by this vulnerability because they use aligned buffers.

The Google Security Team and Red Hat discovered that the eglibc
host name resolver function, getaddrinfo, when processing
AF_UNSPEC queries (for dual A/AAAA lookups), could mismanage its
internal buffers, leading to a stack-based buffer overflow and
arbitrary code execution. This vulnerability affects most
applications which perform host name resolution using getaddrinfo,
including system services.

Adam Nielsen discovered that if an invalid separated time value
is passed to strftime, the strftime function could crash or leak
information. Applications normally pass only valid time
information to strftime; no affected applications are known.

Hector Marco-Gisbert reported that LD_POINTER_GUARD was not
ignored for SUID programs, enabling an unintended bypass of a
security feature. This update causes eglibc to always ignore the
LD_POINTER_GUARD environment variable.

Szabolcs Nagy reported that the rarely-used hcreate and hcreate_r
functions did not check the size argument properly, leading to a
crash (denial of service) for certain arguments. No impacted
applications are known at this time.

The catopen function contains several unbound stack allocations
(stack overflows), causing it the crash the process (denial of
service). No applications where this issue has a security impact
are currently known.

The following fixed vulnerabilities currently lack CVE assignment:

Joseph Myers reported that an integer overflow in the
strxfrm can lead to heap-based buffer overflow, possibly allowing
arbitrary code execution. In addition, a fallback path in strxfrm
uses an unbounded stack allocation (stack overflow), leading to a
crash or erroneous application behavior.

Kostya Serebryany reported that the fnmatch function could skip
over the terminating NUL character of a malformed pattern, causing
an application calling fnmatch to crash (denial of service).

Joseph Myers reported that the IO_wstr_overflow function,
internally used by wide-oriented character streams, suffered from
an integer overflow, leading to a heap-based buffer overflow. On
GNU/Linux systems, wide-oriented character streams are rarely
used, and no affected applications are known.

Andreas Schwab reported a memory leak (memory allocation without a
matching deallocation) while processing certain DNS answers in
getaddrinfo, related to the _nss_dns_gethostbyname4_r function.
This vulnerability could lead to a denial of service.

While it is only necessary to ensure that all processes are not using
the old eglibc anymore, it is recommended to reboot the machines after
applying the security upgrade.

For the oldstable distribution (wheezy), these problems have been fixed
in version 2.13-38+deb7u10.